module ActiveModel::Type::Helpers::TimeValue

def apply_seconds_precision(value)
  return value unless precision && value.respond_to?(:usec)
  number_of_insignificant_digits = 6 - precision
  round_power = 10**number_of_insignificant_digits
  value.change(usec: value.usec - value.usec % round_power)
end

def default_timezone
  if is_utc?
    :utc
  else
    :local
  end
end

def fast_string_to_time(string)
  if string =~ ISO_DATETIME
    microsec = ($7.to_r * 1_000_000).to_i
    new_time $1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, microsec
  end
end

def is_utc?
  ::Time.zone_default.nil? || ::Time.zone_default =~ "UTC"
end

def new_time(year, mon, mday, hour, min, sec, microsec, offset = nil)
  # Treat 0000-00-00 00:00:00 as nil.
  return if year.nil? || (year == 0 && mon == 0 && mday == 0)
  if offset
    time = ::Time.utc(year, mon, mday, hour, min, sec, microsec) rescue nil
    return unless time
    time -= offset
    is_utc? ? time : time.getlocal
  else
    ::Time.public_send(default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
  end
end

def serialize(value)
  value = apply_seconds_precision(value)
  if value.acts_like?(:time)
    zone_conversion_method = is_utc? ? :getutc : :getlocal
    if value.respond_to?(zone_conversion_method)
      value = value.send(zone_conversion_method)
    end
  end
  value
end

def type_cast_for_schema(value)
  value.to_s(:db).inspect
end

def user_input_in_time_zone(value)
  value.in_time_zone
end